I bought a counter pressure bottle filler last week from hoptech.com and am force carbonating in 5 gal. corni's for the first time in quite a while.

What are everyone's methods for carbonation in a keg?

I've done it by chilling my secondary to 35 degrees and
a) just hooking up the co2 at 14psi and letting it sit for a week and
b) hooking up co2 at 25psi and shaking the keg vigorously, letting it sit for 20 minutes and repeating -- drinkable in an hour

I am only a couple of months into CP filling, but I'll share my experience with you for what it's worth.

As far as keg carbonating, I tend to go with your second approace. With the beer as cold as I can get it (only ~40F), I pressurize at just a couple of pounds over my target pressure, and shake every couple of hours for about a day. If I'm dry hopping in the keg, this means I'll be picking hop leaves out of my teeth for a couple of pints, but I can deal with that.

As far as CP filling, again you should have the keg as cold as you can get it to minimize foaming. You'll also get more foaming for the first few fills because the filler starts out warm. I set my cylinder pressure a couple of pounds higher than what I'm sjooting for in the beer, to make up for the frictional loss during transfer and the loss before capping. Cap each beer as you fill, rather than filling a bunch and then capping. I am still trying to master the art of knocking the bottles right before capping to get them to foam up and displace air from the headspace. I am starting to notice a little oxidation in CP-filled bottles after about 2 months, but it is minimal when I have used the oxy-guard barrier caps.

I ent with one of the Listermann Counter Phillers which has a few modifications compared to a standard filler. The most appealing is that there is only a single valve that controls all flows, so you don't need to have 3 hands to use it. The other big modification is that it uses gravity to move beer from keg to bottle, so you have to place the keg up higher than your bottles. I have changed out the rubber stopper that came with the unit for a stopper that is one size larger, because the original stopper kept getting stuck in the mouth of the bottles. I also keep the stopper in place with sanitized tie-wraps used as spacers.